Many parts of the world lack sufficient rainfall during certain times of the year to support the heath of turf, shrubs and other forms of landscape vegetation. Therefore residential and commercial irrigation systems have been widely developed and employed. Typically these irrigation systems comprise a user programmable electronic irrigation controller that turns a plurality of valves ON and OFF in accordance with a watering program. The valves are usually connected to either a municipal water supply or a well and deliver water through buried conduits that terminate in risers equipped with sprinklers. Where the water source is a well, the water is typically pressurized via a pump that is actuated by the irrigation controller through a pump start relay.
It is becoming increasingly important to conserve water, both in terms of lessening adverse environmental impacts and saving money. This is particularly true in more densely populated areas and semi-arid regions where water is availability is scarce in the face of high demand. In an effort to conserve water, many municipalities and water districts have imposed strict limitations that specify the days of the week on which landscape watering can take place, as well as the specific times and durations of permissible watering on those days.
Over the past several years efforts have been made by manufacturers of irrigation products to lessen the amount of water utilized by residential and commercial irrigation systems while avoiding brown lawns and dead shrubs. For example, reliable and efficient rotary stream sprinklers have been developed that are replacing wasteful spray-type sprinklers. These rotary stream sprinklers slowly eject a plurality of small streams of water over an adjustable arc instead of a fan shaped spray of water that is ejected by a spray-type sprinkler which is often partially blown away and/or delivered at too high of a rate. An example of a commercially successful rotary stream sprinkler is the MP ROTATOR® sprinkler manufactured and sold by Hunter Industries, Inc., the assignee of the subject application
In some cases drip irrigation can be used to substantially reduce the amount of water used for irrigation, but only where particular plants and trees are utilized. Some irrigation controllers use rain sensors to inhibit watering during and after periods or rain fall. One commercially successful example of such a sensor is the RAIN CLIK® sensor also manufactured and sold by Hunter Industries, Inc. Irrigation controllers have also been developed that utilize weather-related information to alter the frequency and/or duration of watering taking local weather conditions into account. Some of these systems rely on subscription services that broadcast local weather data. Others receive such information over the Internet. Still others rely on local environmental sensors contained in a miniature on site weather station. These systems utilize formulas that take into account evapotranspiration (ET). The commercially successful ET System™ components manufactured and sold by Hunter Industries, Inc. can be plugged into an existing irrigation controller such as the I-Core® irrigation controller, also sold by Hunter Industries, Inc. The ET System components gather weather data on site and continuously calculate the ideal watering program for nearby landscape vegetation which is communicated to the irrigation controller.
Efforts have also been made by water districts to encourage homeowners to install landscaping that requires less water than conventional landscaping. However, it is difficult to get homeowners to replace their existing turf and shrubs. Moreover, many homeowners do not like rock gardens and desert plants. The latter type of vegetation can usually only survive in geographic areas with arid climates.
While the foregoing efforts have significantly lessened the amount of water used in residential and commercial irrigation, only so much water can be saved by imposing watering restrictions, improving the efficiency of sprinklers and irrigation controllers, and encouraging the use of drought tolerant landscaping.